Diff: drivers/SPI.cpp

Revision:

149:156823d33999

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/SPI.cpp	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,205 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "drivers/SPI.h"
+#include "platform/critical.h"
+
+#if DEVICE_SPI
+
+namespace mbed {
+
+#if DEVICE_SPI_ASYNCH && TRANSACTION_QUEUE_SIZE_SPI
+CircularBuffer<Transaction<SPI>, TRANSACTION_QUEUE_SIZE_SPI> SPI::_transaction_buffer;
+#endif
+
+SPI::SPI(PinName mosi, PinName miso, PinName sclk, PinName ssel) :
+        _spi(),
+#if DEVICE_SPI_ASYNCH
+        _irq(this),
+        _usage(DMA_USAGE_NEVER),
+#endif
+        _bits(8),
+        _mode(0),
+        _hz(1000000) {
+    // No lock needed in the constructor
+
+    spi_init(&_spi, mosi, miso, sclk, ssel);
+    aquire();
+}
+
+void SPI::format(int bits, int mode) {
+    lock();
+    _bits = bits;
+    _mode = mode;
+    SPI::_owner = NULL; // Not that elegant, but works. rmeyer
+    aquire();
+    unlock();
+}
+
+void SPI::frequency(int hz) {
+    lock();
+    _hz = hz;
+    SPI::_owner = NULL; // Not that elegant, but works. rmeyer
+    aquire();
+    unlock();
+}
+
+SPI* SPI::_owner = NULL;
+SingletonPtr<PlatformMutex> SPI::_mutex;
+
+// ignore the fact there are multiple physical spis, and always update if it wasnt us last
+void SPI::aquire() {
+    lock();
+     if (_owner != this) {
+        spi_format(&_spi, _bits, _mode, 0);
+        spi_frequency(&_spi, _hz);
+        _owner = this;
+    }
+    unlock();
+}
+
+int SPI::write(int value) {
+    lock();
+    aquire();
+    int ret = spi_master_write(&_spi, value);
+    unlock();
+    return ret;
+}
+
+void SPI::lock() {
+    _mutex->lock();
+}
+
+void SPI::unlock() {
+    _mutex->unlock();
+}
+
+#if DEVICE_SPI_ASYNCH
+
+int SPI::transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t& callback, int event)
+{
+    if (spi_active(&_spi)) {
+        return queue_transfer(tx_buffer, tx_length, rx_buffer, rx_length, bit_width, callback, event);
+    }
+    start_transfer(tx_buffer, tx_length, rx_buffer, rx_length, bit_width, callback, event);
+    return 0;
+}
+
+void SPI::abort_transfer()
+{
+    spi_abort_asynch(&_spi);
+#if TRANSACTION_QUEUE_SIZE_SPI
+    dequeue_transaction();
+#endif
+}
+
+
+void SPI::clear_transfer_buffer()
+{
+#if TRANSACTION_QUEUE_SIZE_SPI
+    _transaction_buffer.reset();
+#endif
+}
+
+void SPI::abort_all_transfers()
+{
+    clear_transfer_buffer();
+    abort_transfer();
+}
+
+int SPI::set_dma_usage(DMAUsage usage)
+{
+    if (spi_active(&_spi)) {
+        return -1;
+    }
+    _usage = usage;
+    return  0;
+}
+
+int SPI::queue_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t& callback, int event)
+{
+#if TRANSACTION_QUEUE_SIZE_SPI
+    transaction_t t;
+
+    t.tx_buffer = const_cast<void *>(tx_buffer);
+    t.tx_length = tx_length;
+    t.rx_buffer = rx_buffer;
+    t.rx_length = rx_length;
+    t.event = event;
+    t.callback = callback;
+    t.width = bit_width;
+    Transaction<SPI> transaction(this, t);
+    if (_transaction_buffer.full()) {
+        return -1; // the buffer is full
+    } else {
+        core_util_critical_section_enter();
+        _transaction_buffer.push(transaction);
+        if (!spi_active(&_spi)) {
+            dequeue_transaction();
+        }
+        core_util_critical_section_exit();
+        return 0;
+    }
+#else
+    return -1;
+#endif
+}
+
+void SPI::start_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t& callback, int event)
+{
+    aquire();
+    _callback = callback;
+    _irq.callback(&SPI::irq_handler_asynch);
+    spi_master_transfer(&_spi, tx_buffer, tx_length, rx_buffer, rx_length, bit_width, _irq.entry(), event , _usage);
+}
+
+#if TRANSACTION_QUEUE_SIZE_SPI
+
+void SPI::start_transaction(transaction_t *data)
+{
+    start_transfer(data->tx_buffer, data->tx_length, data->rx_buffer, data->rx_length, data->width, data->callback, data->event);
+}
+
+void SPI::dequeue_transaction()
+{
+    Transaction<SPI> t;
+    if (_transaction_buffer.pop(t)) {
+        SPI* obj = t.get_object();
+        transaction_t* data = t.get_transaction();
+        obj->start_transaction(data);
+    }
+}
+
+#endif
+
+void SPI::irq_handler_asynch(void)
+{
+    int event = spi_irq_handler_asynch(&_spi);
+    if (_callback && (event & SPI_EVENT_ALL)) {
+        _callback.call(event & SPI_EVENT_ALL);
+    }
+#if TRANSACTION_QUEUE_SIZE_SPI
+    if (event & (SPI_EVENT_ALL | SPI_EVENT_INTERNAL_TRANSFER_COMPLETE)) {
+        // SPI peripheral is free (event happend), dequeue transaction
+        dequeue_transaction();
+    }
+#endif
+}
+
+#endif
+
+} // namespace mbed
+
+#endif